Galaxy Quest

Wednesday 26 April 2000 23:00 BST

One idea can carry a comedy, if it's good enough.

Galaxy Quest, like Men in Black, just about survives on the single-gag concept. The dog-eared cast of an American TV series that ran from 1979 to 1982 before the sponsors cancelled it now subsist on the convention circuit where their fans, the Questors (who bear a suspicious similarity to nut-case Trekkies), revere (and sometimes ridicule) them. They hate it: still, it's a living.

One day, a new pack of devotees, all looking oddly like shop-window dummies, turn up and inveigle them into visiting what they take to be a mock-up of their old spacecraft Protector. Suddenly, with a digitalised whoosh, they find themselves ingested into a parallel SF universe whose meek and gentle denizens have monitored terrestrial TV channels, taken the space series to be historical documents, and now seek the crew's help in repulsing their tentacular, crustacean-like enemies.

If you think this sounds like Three Amigos, a film John Landis directed in 1985, in which silent-screen cowboys are mistaken for the real McCoys and save a Mexican village from the enemy, you wouldn't be far wrong. But the Steven Spielberg company that made it has had plenty of practice in extraterrestrial spheres, and now relaxes the rules of the universe into an often cheeky and sometimes hilarious genre pastiche. They boldly go where Star Trek ventured, with characters almost libellously modelled on that crew. Tim Allen plays a William Shatner/Patrick Stewart-like commander whose ego expands to fill the Space available;

Sigourney Weaver is the glam communications bimbo in the décolleté space suit that shows a section of her we never suspected she possessed; Alan Rickman is Dr Lazarus, the resident alien whose cerebellum would make Mr Spock prick up his ears; Tony Shalhoub is the engineer who improvises repairs with chewing gum; Sam Rockwell, a walk-on actor who turns into a monster; and Daryl Mitchell, the first black in history to be abducted by aliens.

Director Dean Parisot has had the lavish facilities of George Lucas's Industrial Light and Magic factory to stock the planets with pig-like lizards, cannibal babies - Weaver gurgles maternally at them, until they part their teeth - and an indestructible Rockman who rumbles around like a walking avalanche.

At times, Galaxy Quest becomes just as tacky as the show it satirises, and it's too long to keep the joke from flagging. But whenever this threatens, it beams up an ingenious sight gag or sardonic sound bite. It also bases its fantasy on a truth that's even older than the planets: actors, we know, will go anywhere, do anything, just so long as they draw applause from someone, even from ETs.